bacterial intelligence: they use syringes to infect cells (Animals)

by David Turell , Monday, March 15, 2021, 18:37 (1347 days ago) @ David Turell

A clever deigned system:

https://www.sciencedaily.com/releases/2021/03/210315110259.htm

"Basic, acidic, basic again: for pathogenic bacteria such as Salmonella, the human digestive tract is a sea change. So how do the bacteria manage to react to these changes? A team of researchers from the Max Planck Institute for Terrestrial Microbiology in Marburg led by Andreas Diepold has now provided a possible explanation: pathogenic bacteria can change components of their injection apparatus on the fly -- like changing the tires on a moving car -- to enable a rapid response.

"Some of the best-known human pathogens -- from the plague bacterium Yersinia pestis to the diarrhea pathogen Salmonella -- use a tiny hypodermic needle to inject disease-causing proteins into their host's cells, thereby manipulating them. This needle is part of the so-called type III secretion system (T3SS), without which most of these pathogens cannot replicate in the body.

"Only recently it was discovered that large parts of the T3SS are not firmly anchored to the main part of the system, but are constantly exchanging during function.

***

"In an acidic environment like the stomach, the mobile components do not bind to the rest of the apparatus (including the needle itself), so that the injection system remains inactive. As soon as the bacteria enter a pH-neutral environment -- as it is found in the intestine -, the dynamic proteins reassemble, so that the T3SS can quickly become active at these sites -- to the possible distress of the infected person.

"The researchers speculate that the newly discovered effect may allow the bacteria to prevent an energy-consuming "misfiring" of the secretion system in the wrong environment, which could even activate the host's immune response. On the other hand, the mobility and dynamics of the structure allows the system to be rapidly reassembled and activated under appropriate conditions.

"Protein mobility and exchange are increasingly being discovered in complexes and nanomachines across all domains of life; however, the utility of these dynamics is mostly not understood. The new results from Marburg show how protein exchange allows to respond flexibly to external circumstances -- an immense advantage, not only for bacteria."

Comment: Shapiro's research validated again. I still approach this as a God-given design.